Production has been delayed on Season 8 of CBS' 'The Big Bang Theory' as some of its stars negotiate new contracts. / Michael Yarish, Warner Bros. Entertainment

by Bill Keveney, USA TODAY

by Bill Keveney, USA TODAY

The Big Bang Theory delayed the scheduled start of Season 8 production Wednesday as actors and producing studio Warner Bros. discuss new pacts.

"Due to ongoing contract negotiations, production on The Big Bang Theory - which was originally scheduled to begin today - has been postponed," Warner Bros. Television said in a statement.

Contracts for five of the top-rated comedy's stars â?? Jim Parsons, Johnny Galecki, Kaley Cuoco-Sweeting, Simon Helberg and Kunal Nayyar â?? expired after last season, and the actors and the studio have yet to agree on new salaries. Mayim Bialik and Melissa Rauch are signed.

At this point, the delay would not affect the CBS comedy's Sept. 22 premiere date. Bang, which will start the fall season on a Monday, is scheduled to open with a one-hour premiere, leading into the series premiere of Scorpion. Bang will move to Thursdays in late October, after CBS' Thursday NFL coverage ends.

CBS program chief Nina Tassler didn't seemed particularly bothered that the contracts hadn't been worked out when she spoke to TV writers at the summer press tour two weeks ago.

"When you have successful shows, you have renegotiations. We're feeling very confident that everything will work out. These deals manage to get done somehow miraculously year after year," she said.